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    <title>CDN 内容分发网络 - 加速互联网的基础设施</title>
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<body>
    <!-- Hero Section -->
    <section class="hero-gradient text-white py-20 px-6">
        <div class="max-w-6xl mx-auto text-center">
            <div class="float-animation inline-block mb-6">
                <i class="fas fa-network-wired text-6xl opacity-90"></i>
            </div>
            <h1 class="text-5xl md:text-6xl font-bold mb-6 tracking-tight">
                CDN 内容分发网络
            </h1>
            <p class="text-xl md:text-2xl opacity-90 max-w-3xl mx-auto leading-relaxed">
                加速互联网的基础设施，让内容触手可及
            </p>
            <div class="mt-10 flex justify-center space-x-8 text-sm">
                <div class="flex items-center">
                    <i class="fas fa-globe mr-2"></i>
                    <span>全球覆盖</span>
                </div>
                <div class="flex items-center">
                    <i class="fas fa-bolt mr-2"></i>
                    <span>极速传输</span>
                </div>
                <div class="flex items-center">
                    <i class="fas fa-shield-alt mr-2"></i>
                    <span>安全可靠</span>
                </div>
            </div>
        </div>
    </section>

    <!-- Main Content -->
    <main class="max-w-6xl mx-auto px-6 py-12">
        <!-- Introduction -->
        <section class="bg-white rounded-2xl shadow-xl p-8 md:p-12 mb-12">
            <p class="text-lg leading-relaxed text-gray-700">
                <span class="drop-cap">C</span>DN（Content Delivery Network，内容分发网络）是一个分布式的网络架构，旨在提高内容的交付速度和可靠性，改善用户的访问体验。它通过将内容分发到离用户更近的节点（称为边缘节点或缓存服务器），减少延迟和提高传输效率。通过分布式的边缘节点来缓存和优化内容的交付，CDN不仅提高了内容传输的速度和可靠性，还增强了系统的安全性和抗攻击能力。
            </p>
        </section>

        <!-- Core Functions -->
        <section class="mb-12">
            <h2 class="text-3xl font-bold mb-8 text-center">
                <span class="text-gradient">CDN 的核心功能</span>
            </h2>
            
            <div class="grid md:grid-cols-2 lg:grid-cols-3 gap-6">
                <!-- 内容分发 -->
                <div class="bg-white rounded-xl p-6 card-hover">
                    <div class="text-4xl mb-4 feature-icon">
                        <i class="fas fa-share-alt"></i>
                    </div>
                    <h3 class="text-xl font-bold mb-3">内容分发</h3>
                    <p class="text-gray-600 mb-3">通过全球分布的服务器网络，智能缓存和分发内容。</p>
                    <ul class="space-y-2 text-sm text-gray-500">
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>缓存静态和动态内容</li>
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>智能负载均衡</li>
                    </ul>
                </div>

                <!-- 性能优化 -->
                <div class="bg-white rounded-xl p-6 card-hover">
                    <div class="text-4xl mb-4 feature-icon">
                        <i class="fas fa-rocket"></i>
                    </div>
                    <h3 class="text-xl font-bold mb-3">性能优化</h3>
                    <p class="text-gray-600 mb-3">显著提升内容加载速度，优化用户体验。</p>
                    <ul class="space-y-2 text-sm text-gray-500">
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>降低访问延迟</li>
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>提高传输速度</li>
                    </ul>
                </div>

                <!-- 可靠性保障 -->
                <div class="bg-white rounded-xl p-6 card-hover">
                    <div class="text-4xl mb-4 feature-icon">
                        <i class="fas fa-server"></i>
                    </div>
                    <h3 class="text-xl font-bold mb-3">可靠性保障</h3>
                    <p class="text-gray-600 mb-3">确保服务高可用，抵御各种网络攻击。</p>
                    <ul class="space-y-2 text-sm text-gray-500">
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>高可用性架构</li>
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>抗DDoS攻击</li>
                    </ul>
                </div>

                <!-- 安全防护 -->
                <div class="bg-white rounded-xl p-6 card-hover">
                    <div class="text-4xl mb-4 feature-icon">
                        <i class="fas fa-shield-alt"></i>
                    </div>
                    <h3 class="text-xl font-bold mb-3">安全防护</h3>
                    <p class="text-gray-600 mb-3">全方位保护数据传输和内容安全。</p>
                    <ul class="space-y-2 text-sm text-gray-500">
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>数据加密传输</li>
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>访问控制机制</li>
                    </ul>
                </div>

                <!-- 全球覆盖 -->
                <div class="bg-white rounded-xl p-6 card-hover">
                    <div class="text-4xl mb-4 feature-icon">
                        <i class="fas fa-globe-americas"></i>
                    </div>
                    <h3 class="text-xl font-bold mb-3">全球覆盖</h3>
                    <p class="text-gray-600 mb-3">遍布全球的节点网络，无缝覆盖各地用户。</p>
                    <ul class="space-y-2 text-sm text-gray-500">
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>地理分布优化</li>
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>就近访问服务</li>
                    </ul>
                </div>

                <!-- 智能调度 -->
                <div class="bg-white rounded-xl p-6 card-hover">
                    <div class="text-4xl mb-4 feature-icon">
                        <i class="fas fa-brain"></i>
                    </div>
                    <h3 class="text-xl font-bold mb-3">智能调度</h3>
                    <p class="text-gray-600 mb-3">基于AI的智能路由和内容分发策略。</p>
                    <ul class="space-y-2 text-sm text-gray-500">
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>智能路由算法</li>
                        <li><i class="fas fa-check-circle text-green-500 mr-2"></i>动态内容加速</li>
                    </ul>
                </div>
            </div>
        </section>

        <div class="section-divider"></div>

        <!-- Working Principle -->
        <section class="mb-12">
            <h2 class="text-3xl font-bold mb-8 text-center">
                <span class="text-gradient">CDN 工作原理</span>
            </h2>
            
            <div class="bg-white rounded-2xl shadow-xl p-8 md:p-12">
                <div class="mermaid">
                    graph LR
                        A[用户请求] --> B{CDN智能路由}
                        B --> C[最近边缘节点]
                        C --> D{内容是否缓存}
                        D -->|已缓存| E[直接返回内容]
                        D -->|未缓存| F[回源获取]
                        F --> G[源服务器]
                        G --> H[缓存到边缘节点]
                        H --> E
                        E --> I[用户接收内容]
                        
                        style A fill:#f9f,stroke:#333,stroke-width:2px
                        style I fill:#9f9,stroke:#333,stroke-width:2px
                        style B fill:#bbf,stroke:#333,stroke-width:2px
                        style C fill:#fbf,stroke:#333,stroke-width:2px
                </div>
                
                <div class="grid md:grid-cols-3 gap-6 mt-8">
                    <div class="text-center">
                        <div class="bg-purple-100 rounded-full w-16 h-16 flex items-center justify-center mx-auto mb-4">
                            <i class="fas fa-database text-purple-600 text-2xl"></i>
                        </div>
                        <h4 class="font-bold mb-2">内容缓存</h4>
                        <p class="text-sm text-gray-600">智能缓存策略，定期更新内容，确保用户获得最新数据</p>
                    </div>
                    <div class="text-center">
                        <div class="bg-purple-100 rounded-full w-16 h-16 flex items-center justify-center mx-auto mb-4">
                            <i class="fas fa-route text-purple-600 text-2xl"></i>
                        </div>
                        <h4 class="font-bold mb-2">请求路由</h4>
                        <p class="text-sm text-gray-600">基于地理位置和网络状况，智能选择最优节点</p>
                    </div>
                    <div class="text-center">
                        <div class="bg-purple-100 rounded-full w-16 h-16 flex items-center justify-center mx-auto mb-4">
                            <i class="fas fa-sync-alt text-purple-600 text-2xl"></i>
                        </div>
                        <h4 class="font-bold mb-2">更新失效</h4>
                        <p class="text-sm text-gray-600">灵活的缓存策略，支持主动清除和自动更新</p>
                    </div>
                </div>
            </div>
        </section>

        <div class="section-divider"></div>

        <!-- Application Scenarios -->
        <section class="mb-12">
            <h2 class="text-3xl font-bold mb-8 text-center">
                <span class="text-gradient">CDN 应用场景</span>
            </h2>
            
            <div class="grid md:grid-cols-2 gap-6">
                <div class="bg-gradient-